columnNumber = 701
letter='ABCD'
list=[]
list_asc=[]
num=0

for i in letter:
    list.append(i)
list=list[-1::-1]
print(list,len(list))

for j in list:
    list_asc.append(ord(j)-ord('A')+1)
print(list_asc)

for x in range(len(list)):
    num += list_asc[x]*26**x
    print(num)


"""for j in range(len(list)-1,-1,-1):
    print(j)"""